Process for hydrolyzing nitriles

ABSTRACT

Nitriles of the formula R-CN)x are hydrolyzed with water in the presence of soluble copper ions in the pH range of 1 to 12.5.

United States Patent [191 Greene et al.

[ Reissued Aug. 19, 1975 1 PROCESS FOR HYDROLYZING NITRILES 75] Inventors: Janice L. Greene, Warrensville Heights; Murrel Godfrey,

Cleveland, both of Ohio [73] Assignee: The Standard Oil Company,

Cleveland, Ohio [22] Filed: Apr. 26, 1974 [21] Appl. No.: 464,650

Related U.S. Patent Documents Reissue of:

[64] Patent N0.: 3,381,034

Issued: Apr. 30, 1968 Appl. No.: 468,546 Filed: June 30, 1965 [52] US. Cl...... 260/557 R; 260/561 R; 260/561 N; 260/561 K [51] Int. Cl. C07c 103/08 OTHER PUBLICATIONS Watanabe, Bull. Chem. Soc. Jap., V01. 37 pp. 1325-29 (9/ l 964) Primary Examiner-Harry I. Moatz Attorney, Agent, or Firm-John F. Jones; Sherman J. Kemmer 57 ABSTRACT Nitriles of the formula R-(-CN) are hydrolyzed with water in the presence of soluble copper ions in the pH range of] to 12.5.

12 Claims, N0 Drawings PROCESS FOR HYDROLYZING NITRILES Matter enclosed in heavy brackets I: appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

' The present invention relates to a novel process for hydrolysis of nitriles with water and a copper catalyst and more particularly pertains to the formation of amides, acids and other hydrolysis products from nitriles by hydrolysis with water in the presence of copper ions.

The hydrolysis of nitriles to form the corresponding amides, acids and other hydrolysis products in the pres ence of acids and bases is well known to those skilled in the art. The hydrolysis of nitriles by the use of mineral acids such as strong sulfuric acid is well known and the usual procedure in working up the amide product is to neutralize the sulfuric acid with a base and then to separate the sulfate salt from the amide product by some means. In a commercial hydrolysis of this type, it is often useful to use ammonia to neutralize the sulfuric acid and then to use the ammonium sulfate or ammonium hydrogen sulfate as a fertilizer component because the regeneration of sulfuric acid for recycling is too costly. The separation of the ammonium sulfate from the amide product is not always simple, particularly in the case in which the amide product is water soluble.

The solubility of copper halides in acetonitrile has been studied (Ber. 47. 247256, 1914) and copper powder has been used as a polymerization inhibitor in the sulfuric acid hydrolysis of nitriles such as acrylonitrile.

The present process is a novel catalytic process which involves the hydrolysis of nitriles with water in the presence of a copper salt which may also contain metallic copper. The hydrolysis products of the present process are relatively pure and are easily recovered without any appreciable amounts of by-products.

The nitriles useful in the present invention are those having the structure R-(-CN) wherein R is a hydrocarbon group having from 1 to carbon atoms and x is a number of from 1 to 4. More preferred are nitriles of the foregoing structure wherein R is a member selected from the group consisting of an aromatic hydrocarbon radical, an alkyl radical, an alicyclic radical and an olefin radical having from 1 to 8 carbon atoms and x is a number from 1 to 2. Specific preferred nitriles useful in the present invention include acetonitrile,

2 Cu Z Cu Cu Thus, it is only necessary to have present as catalyst initially cuprous salts alone or a combination of metallic copper and a water soluble cupric salt in the instant process. It is also contemplated that combinations of metallic copper and cuprous salts, cuprous salts and cu pric salts as well as metallic copper, cuprous salts and cupric salts can be used to advantage in the instant process. Stated differently, suitable catalytic combinations include Cu Cu, Cu Cu, Cu Cu and Cu Cu Cu etc. We have found that metallic copper when used alone is ineffective in this process.

Bearing in mind the foregoing, any cupric or cuprous salt may be used so long as it is at least slightly soluble in water, the nitrile, or both water and the nitrile. Thus, although CuCl, Cul and CuCN are practically insoluble in water'(Gmelin Handbuch der Anorganischen Chemie," Vol. 60, pages406 and 854) they can still catalyze the hydrolysis of nitriles to amides.

The copper ions which catalyze this reaction may be coordinated with water and other ligands known to form complexes with copper ions such as ethylene, carbon monoxide, chloride ions, ammonia, amines, and unsaturated nitriles, etc., without destroying their catalytic activity.

Although copper salts in aqueous solution are acidic (Moeller, Qualitative Analysis, pages l034, 1958) the catalysis of nitrile hydrolysis by copper salts is not a function of acidity alone because we have been un able to detect the formation of nitrile hydrolysis products at a pH of 3 in the absence of copper ions. In the presence of the catalysts embodied herein, nitriles can be hydrolyzed within the pH range of from about 1 to about 12.5.

The amount of copper ion catalyst useful in the present invention falls within rather broad ranges. The amount of catalyst used appears to have little or no effect on the conversion of nitrile to hydrolysis products. At the lower catalyst levels, however, the reaction times required for significant hydrolysis may be quite long. The upper end of the range of copper ion catalyst will depend upon convenience and reactor design. The use of a fluidized bed of a solid copper ion catalyst with or without a carrier and the contacting of this fluidized catalyst bed with the nitrile and water vapor at an elevated temperature is contemplated in the present in vention.

The role of copper metal in the catalyst is not clearly understood at the present time, although its presence appears to facilitate the desired reaction. It is possible that this beneficial effect is attained by stabilization of the cuprous ion state through partial reversal of the equilibrium shown above. No pretreatment of the metallic copper is necessary, although it is recommended that surface dirt, etc., be removed with a solvent such as chloroform prior to use of the copper metal as a catalyst component in the instant process. Coating of the copper surface with mercury is undesirable. The physical state of the metallic copper is not critical in the instant process. The copper metal may be present in any convenient form such as wire, turnings, powder, etc. The amount of copper metal present in the catalyst is not critical although for convenience and economy it is preferred that there be present from about 0.5 to 1.0 mole of copper metal per mole of copper ion or ions.

The present process cna be conducted under a rather wide range of temperatures, but the desired reaction may be quite slow at the low temperatures. The hydrolysis temperature can be varied from about 25C to 220C and the preferred range is from about 100 to about 150C.

The reaction pressure in the instant process is not critical and can range from atmospheric and below up to about 2000 psig and higher. For the nitriles which are volatile the use of elevated pressures is advantageous in that more of the nitrile is kept in the liquid phase during the reaction.

The relative amounts of water and nitrile can be varied considerably. Less than stoichiometric amounts of water can be employed if desired, depending upon convenience and reactor design, but stoichiometric quantities are required for complete reaction. The stoichiometry of the process is shown in the following equations employing for convenience an illustrative nitrile R+CN) of the foregoing type wherein x is l:

Thus, it is preferred in the present process that at least one mole of water be used per chemical equivalent of cyanide present in the nitrile.

Other solvents in addition to the water and R(CN reactants may be employed in the instant process if deinstant process. Other by-products which have been found include carboxylic acid esters when alcohol is present in the reaction medium, and in the case of the hydrolysis of an alpha, beta-olefinically unsaturated ni trile. such as acrylonitrile the by-products uocu cn cn and O(CH CH CN) have been found to be present in small amounts.

In the following examples which will illustrate the process of this invention, the amounts of ingredients are expressed in moles unless otherwise indicated; conversions are expressed in mole percent.

EXAMPLE I The nitrile, water and catalyst were placed in a reaction vessel equipped with heating means, stirrer and cooling means. The vessel was then pressured with nitrogen to about psig followed by venting and repressuring with nitrogen until substantially all of the air had been removed. After the final venting, the vessel was sealed and heated to the reaction temperature with continuous stirring. Samples of the reaction mixture were removed from time to time and were subjected to vapor chromatographic analysis and infrared analysis. When the desired conversion level had been reached in the reaction, the mixture was cooled and the hydrolysis product was separated from the unreacted nitrile, the catalyst and other products by suitable means which may include distillation, crystallization, extraction, ion

sired. Suitable auxiliary solvents include dioxane, di- 30 exlchange t t th f methoxyethane, acetone, tetrahydrofuran, the did n a represeln a 1 {I e 9 g"? g l I methyl ether of diethylene glycol, chloroform, pyridine me was emp Oye uslzxg t e mtn es gwen m a e at and the like a temperature of C, under autogenous pressure The primary hydrolysis products of the present proemploying a Charge of of water, 150 of cess are the amide and the carboxylic acid. In the prep- 35 10 grams 0f pp (when used) n 15 grams of aration of the amide some of the acid is usually prothe pp Salt (when U- The Com/510m f amlde duced as a by-product. In addition to the acid, small given in Table I are expressed in mole percent based on amounts of some other by-products are produced in the the nitrile.

Table 1 Reaction Conversion Time of Nitrile Nitrile Catalyst (hours) to Amide Acrylonitrile CuCl 8 4.2 Acetonitrile CuCl l8 (200C) 8.65 Succinonitrile CuCl 20 (200C) 52 Acrylonitrile CuCl 7 4 Acrylonitrile CuCl CuCl 10 0.5 Acrylonitr-ile CuCl Cu 13 65.3 Acrylonitrile CuCl Cu 4 37 Acrylonitrile CuCl Cu 8 22 Acrylonitrile Cu 1 3 None Acrylonitrile CuSO, Cu 8 12.3 Acrylonitrile Cu] 8 0.5 Acrylonitrilc CuCN Cu 21 0.5 Acrylonitrile CuC]'CH %HCN* 8 9.8 Acrylonitrile CuCl'CH =CHCN Cu* 8 12.7 Acrylonitrile CuCl Cu CHFCH2** 4 23.4 Acrylonitrile CuCl Cu CQ*** 4 18.4 Acrylonitrile CuCl Cu NaCl 18 22 (5 moles NaCl per mole of CuCl) In this experiment 5.8 mole of acrylic acid, 12 mole of hydracrylonitrile, 8.8 mole of acrylonitrile and 8.1% of water soluble polymer were also recovered.

"ln this experiment 9.9 rnnle acrylic acid, 16.7 mole hydracrylic acid and 52.3 rnolc acrylonitrile were also recovered. Prepared as in Ber. 94, 1893 (I961). *900 psig ""800 psig EXAMPLE 1] Table V The procedure of Exarnp1e I was repeated and the pH Reaction Reaction of the reaction medium was varied. The nitrile used was Temperature Time Conversion acrylonitrile and the results of several experiments are 5 (cc) (hours) to Acrylamlde given in Table II. 72 2O 0 2 125 13 48 Table II 200 0.25 Recovered only water soluble polymer. Reaction Time Conversion Catalyst pH (hours) to Acrylamidc CuCI Cu 0.1 N HC1 1.2 6 10 EXAMPLE VI CuC1+ Cu Acetic Acid 1.5 5 9.6 cucl Cu Acetic Acid 52 4 SJ The procedureof Example was followed and several sodium solvents in addltion to the nitrile and water were em- Aceme ployed. The results of these experiments are given in CuCl- Cu Pyridine 7.6 6 1 1.6 T bl VI CuCl Cu NH4OH* 12.5 21 0.5 a e Only 0.001 N "CI 3.1 27 NUDE Table The starting nitrile was acetonitrile. 0

Reaction Time Conversion EXAMPLE HI Solvent (hours) to Acrylamide The rocedure of Exam 1e 1 was re eated testin the Me'hanol 2 p p p g Dioxane 6 5.9 effect of varlation of the mole ratio of copper 1011 to m- Dioxane* 5 18.5 trile wherein the nitrile was acrylonitrile. The results of "z gfg g g 1: several experiments are given in Table III. Chloroform 4 12.5 Pyridine 6 11.6 Table III 800 psig at 125C.

. Reaction 3O Mole Ratio Time Conversion Copper lon/Acrylonitrile (hours) to Acrylamide EXAMPLE VI] 0 016 l l 24 4 The procedure of Example I was followed using vari 0:067 8 ations in the mole ratio of water to acrylonitrile and the 0.188 8 3O results are given in Table VII. 1.0 13 43.6

Table VIII Reaction EXAMPLE [V Mole Ratio Time Conversion 4 Water/Acrylonitrile (hours) to Acrylamide O The procedure of Example 1 was repeated testing the 1 effect of pretreatment of the copper metal used in the g i g catalyst. The copper metal was copper turnings with 3.7/1 6 14.1 one exception. The results are shown in Table IV. 20/] 5 Table IV EXAMPLE VIII Grams of Reaction Metallic Tim Conversion The procedure of Example I was followed using the Copper Pretreatment of Copper (hours) to Acrylamide various nitriles given in Tabla VI".

10 None 6 17.2 Table VIII 40 None 6 13.0 10* None 4 10.0 10 Boiled in CHCl;,, 4 15.0 Reaction 90 min. Time Conversion 1O Boiled in conc. HCl, 8 10.0 NIT-r116 (hours) to Amide 90 min. washed with distilled H2O Acrylomtrile 13 to pH Acetomtnle I 13 16.7 10 A 26 None Methacrylomtrlle 21 7.8

$3532 M Methacrylonin'ile 22* 12.4 Crotononitrile 45 22.6

Succinonitrile 20* 52 Copper owder. mesh. 60 Benzonitrile 20** 2 5] 1 ,2-Dicyanocyclobutane 20** 2. 3

V 21 hours at C, 1 hour at 210C.

"*Reaction temperature 200C. The procedure of Example 1 was followed employing acrylonitrile and a catalyst composed of 10 g. of copper 65 In Table VII] the reaction product from succinonimetal and 15 g. of CuC1 The effect of reaction temtrile was succinamide as identified by infrared. 1 In the perature was studied and the results are given in Table case of benzonitrile, the reaction charge was 0.19 mole v of nitrile, 2.78 moles of water, 0.041 mole of CuCl and 0.063 mole of Cu. 1 1n the case of 1,2- dicyanocyclobutane the reaction charge was 0.47 mole of nitrile, 2.78 moles of water and 0.041 mole of CuCl The product from the 1,2-dicyanocyclobutane was 1,2- cyclobutanedicarboxamide as identified by infrared spectroscopy.

We claim:

I: 1. The process for hydrolyzing a nitrile having the structure R-(CN), wherein R is an alkyl radical having from 1 to 8 carbon atoms, an alicyclic radical having from 4 to 8 carbon atoms, an olefinic radical having from 2 to 8 carbon atoms or an aromatic hydrocarbon radical having from 6 to 10 carbon atoms and x is a number from 1 to 4 comprising contacting said nitrile with water at a pH of from about 1 to about 12.5 in the presence of a copper ion, said copper ion being at least partially soluble in water, the nitrile or in both water and the nitrile and said copper ion being composed of copper in a combined valence state of Cu Cu Cu Cu, Cu Cu, or Cu Cu* Cu.

2. The process for hydrolyzing a nitrile selected from the group consisting of acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylonitrile, crotononitrile, maleic dinitrile, glutaronitrile, succinonitrile, adiponitrile, and cyclobutane-l,2-dicyanide I: and benzonitrile comprising contacting said nitrile with water at a pH of from about 1 to about 12.5 in the presence ofa copper ion, said copper ion b ing at least partially soluble in water, the nitrile or in both water and nitrile and said copper ion being composed of copper in a combined valence state of Cu Cu, Cu Cu,

Cu Cu, or Cu Cu Cu at a temperature of from about 25C to about 220C at from about atmospheric pressure up to about 2000 psig.

3. The process of claim 2 wherein the temperature is from about C to about C.

4. The process of claim 3 wherein the copper ion is a mixture of cuprous and cupric ions.

5. The process of claim 4 wherein there is also present from 0.5 to 1.0 mole of copper metal per mole of copper ions.

6. The process of claim 5 wherein there is employed at least one mole of water per chemical equivalent of cyanide present in the nitrile.

7. The process of claim 6 wherein the nitrile is acrylonitrile.

8. The process of claim 6 wherein the nitrile is acetonitrile.

9. The process of claim 6 wherein the nitrile is methacrylonitrile.

10. The process of claim 6 wherein the nitrile is crotononitrile.

11. The process of claim 6 wherein the nitrile is suc cinonitrile.

I: 12. The process of claim 6 wherein the nitrile is benzonitrile.

13. The process of claim 6 wherein the nitrile is 1,2- dicyanocyclobutane.

14. The process of claim 6 wherein the nitrile is adiponitrile. 

2. THE PROCESS FOR HYDROLYZING A NITRILE SELECTED FROM THE GROUP CONSISTING OF ACETONITRILE, PROPIONITRILE, BUTYRONITRILE, ACRYLONITRILE, METHACRYLONITRILE, CROTONONITRILE, MALEIC DINITRILE, GLUTARONITRILE, SUCCINONITRILE, ADIPONTRILE, AND CYCLOBUTANE-1,2-DICYANIDE ( AND BENZONITRILE ) COMPRISING CONTACTING SAID NITRILE WITH WATER AT A PH OF FROM ABOUT 1 TO ABOUT 12.5 IN THE PRESENCE OF A COPPER ION, SAID COPPER ION BEING AT LEAST PARTIALLY SOLUBLE IN WATER, THE NITRILE OR IN BOTH WATER AND NITRILE AND SAID COPPER ION BEING COMPOSED OF COPPER IN A COMBINED VALENCE STATE OF CU* + CU+, CU$ +CU++, CU+ + CU++, OR CU* + CU+ + CU++ AT A TEMPERATURE OF FROM ABOUT 25*C TO ABOUT 220*C AT FROM ABOUT ATMOSPHERIC PRESSURE UTO ABOUT 2000 PSIG.
 3. The process of claim 2 wherein the temperature is from about 100*C to about 150*C.
 4. The process of claim 3 wherein the copper ion is a mixture of cuprous and cupric ions.
 5. The process of claim 4 wherein there is also present from 0.5 to 1.0 mole of copper metal per mole of copper ions.
 6. The process of claim 5 wherein there is employed at least one mole of water per chemical equivalent of cyanide present in the nitrile.
 7. The process of claim 6 wherein the nitRile is acrylonitrile.
 8. The process of claim 6 wherein the nitrile is acetonitrile.
 9. The process of claim 6 wherein the nitrile is methacrylonitrile.
 10. The process of claim 6 wherein the nitrile is crotononitrile.
 11. The process of claim 6 wherein the nitrile is succinonitrile.
 13. The process of claim 6 wherein the nitrile is 1,2-dicyanocyclobutane.
 14. The process of claim 6 wherein the nitrile is adiponitrile. 